Integral fan-heat exchanger

ABSTRACT

An axial flow fan having a set of rotating blades and a set of stationary blades is combined with a combustion chamber, utilizing the rotating portion of the fan and the stationary blade portion of the fan as heat exchangers. The functions of air movement and air heating are thereby combined into one simple apparatus.

United'States Patent Inventors Harry C. Lohman;

Irvin Cooley, La Crosse, Wis. Appl. No. 804,402 Filed Mar. 5, 1969 Patented Feb. 2, 1971 Assignee The Trane Company La Crosse, Wis.

a corporation of Wisconsin INTEGRAL FAN HEAT EXCHANGER 6 Claims, 4 Drawing Figs.

Int. CL... F24h 3/06 Field otSearch 126/110, 1 10B, 1 10D [56] References Cited UNITED STATES PATENTS 1,895,565 1/1933 Bell 126/110D 2,263,998 11/1941 McCollum... 126/110D 2,453,913 11/1948 l-ligley l 126/110D 2,780,217 2/1957 Witherell 126/110D Primary ExaminerCharles J. Myhre Attorneys-Arthur 0. Andersen, Carl M. Lewis and Lee E.

Johnson ABSTRACT: An axial flow fan having a set of rotating blades and a set of stationary blades is combined with a combustion chamber, utilizing the rotating portion of the fan and the stationary blade portion of the fan as heat exchangers. The functions of air movement and air heating are thereby combined into one simple apparatus.

PATENTEU FEB 2197! sum 1 UF 2 FIG.

INVENTOR. HARRY C. LOHMAN IRVIN COOLEY PATENTEDLFEB 2 I9?! SHEET 2 BF 2 INVENTOR. HARRY C. LOHMAN IRVIN COOLEY ATTORNEY INTEGRAL FAN HEAT EXCIIANGER BACKGROUND OF THE INVENTION 1 Field of the Invention This invention relates to air heating and handling apparatus and more particularly to a fan construction combined with a heat exchanger to simultaneously move and heat a fluid force past the apparatus.

2. Description of the Prior Art Past attempts at combining the function of a fan and that of a heat exchanger to simultaneously heat and move a fluid stream. have resulted in cumbersome and impractical apparatus. It is therefore desirable to possess a fan structure which efficiently handles a fluid stream and which can be integrally combined with a heat exchanger to simultaneously move and heat the fluid stream. It is also desirable that such an apparatus having a configuration which can readily be combined with a second heat exchange means for cooling the fluid being moved by the fan.

SUMMARY OF THE INVENTION This invention therefore provides an integral fan-heat exchanger comprising a first substantially cylindrical casing having an inlet and an outlet, a combustion chamber mounted within the first casing, means for introducing a combustible fluid into the chamber and burning it therein, the chamber having an outlet for products of combustion, a primary heat exchanger mounted for rotation within said first casing, the primary heat exchanger surrounding a portion of the chamber including the chamber outlet and thereby being in internal fluid communication with the chamber, the primary heat exchanger having an annularly shaped outlet located between one end of the primary heat exchanger and the outside of the chamber, the heat exchanger outlet being downstream of the chamber outlet, the primary heat exchanger having fluid moving blades extending radially therefrom and spaced from the first casing, the blades in heat exchange relationship with the primary heat exchanger, a second heat exchanger mounted concentrically between the chamber and the first casing, the secondary heat exchanger in fluid communication with the primary heat exchanger, means for exhausting products of combustion from the secondary heat exchanger, and motor means for rotating the primary heat exchanger.

The present invention can further include in combination a second casing in which the integral fan heat exchanger is mounted. The second casing having an inlet for air to be conditioned and an outlet for conditioned air, the inlets of the first and second casings in fluid communication through an inlet passage, the outlets of the first and second casings in fluid communication through an outlet passage, means for introducing a combustion fluid and a combustible fluid into the combustion chamber from outside the first casing, means for exhausting products of combustion to the outside of the first casing. This combination can further include a cooling coil adapted to be connected to a source of cooled fluid which can be mounted in heat exchange relationship in the inlet passage, and means for returning cooled fluid from the coil to the source of cooled fluid.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial cross-sectional elevational view of the integral fan heat exchanger of the instant invention combined in a unit with an outer casing and a cooling coil. The inner casing, outer casing and cooling coil are shown in cross section to expose the fan-heat exchanger.

FIG. 2 is a cross-sectional elevation view of the integral fanheat exchanger of the instant invention.

FIG. 3 is a horizontal cross-sectional view of the apparatus of the present invention taken along section A-A of FIG. 1.

FIG. 4 is a horizontal cross-sectional view of a portion of the rotating fan-heat exchanger of the instant invention taken along section 343 of FIG. 2. The upper portion of the combustion chamber in FIG. 4 has been removed for clarity.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. 1 and 2, an inner, substantially cylindrical casing 2 is supported by arms 4 within an outer casing or housing 6. Arms 4 are attached to casings 2 and 6 by welds 8, or other suitable fastening means. Arms 10 are mounted toward the upper portion of casing 2 and support a bearing 12 concentrically within casing 2. A shaft 14 is mounted for rotation in bearing 12 and is drivingly connected at one end to motor 16 and at the other end to a rotating fan member 18. The motor 16 is supported at the top of housing 6 by brackets 20 and fasteners 22.

An annularly shaped, stationary heat exchanger 24 is concentrically positioned within casing 2. It is held in position by stationary blade members 26 which are fastened at their respective ends to and extend between annular heat exchanger 24 and casing 2. The blades 26 are preferably formed of a heat conductive material and are in heat exchange relationship with the heat exchanger 24. A combustion chamber 28 is mounted within rotating fan member 18 and stationary heat exchanger 24. It is fastened at its lower portion to stationary heat exchanger 24. This connection forms a fluidtight seal around the lower periphery 30 of the combustion chamber 28, sealing one end of heat exchanger 24.

I-Iemispherical member 32 can be attached to the bottom of the combustion chamber to improve the fluid flow characteristics of the fan, although it is not necessary. The combustion chamber 28 can be manufactured from a stainless steel or can be a hard refractory material similar to that used for combustion chambers in oil fired furnaces.

The combustion chamber has an inlet passage 34 through which combustion fluid, most commonly air, enters. Inserted in inlet passage 34 is a combustible fluid burner 36. The burner is secured to the wall of passage 34 and to casing 2 by brackets 38 and 40 respectively. The combustible fluid burner 36 has attached to its inner end a deflector 42 which serves to evenly distribute the flame throughout the combustion chamber 28. Combustible fluid, for example, natural gas, is supplied to the burner 36 through nozzle 44 from a source 46. A pilot mechanism for initially firing burner 36 is shown at 48. Combustion air passage 34 is in fluid communication with plenum 50 which in turn communicates with the source of combustion air through passage 52.

The combustion chamber 28 is in fluid communication with the rotating fan member 18 through the chamber outlet 54. The products of combustion issuing from chamber outlet 54 are forced radially outward by the action of impellers 56 attached to the inner top portion of rotating member 18. The action of impellers 56 and the flared portion 58 of the combustion chamber assist the combustion products into hollow blades 60, although the combustion products can be drawn from the chamber by the action of the hollow blades alone. Hollow blades 60 and rotating member 18 are made from any heat conductive material suitable to effect heat transfer to a fluid which is passing over the outer portion of the rotating member. Blades 60, of course, have a pitch which forces a fluid to be heated past rotating member 18, blades 60, secondary heat exchanger 24, and blades 26 in the direction of the arrow 62 (FIG. 1).

Since the products of combustion are drawn from the combustion chamber, the burner operates under forced draft rather than atmospheric conditions. This features readily adapts the fan-heat exchanger of this invention to installation and operation in any altitude.

After leaving the upper portion of rotating member 18 and the hollow blade 60, the combustion gases pass through annularly shaped passage 64 into the annularly shaped interior portion 66 of stationary heat exchanger 24. The combustion products are then exhausted through passage 68 to the atmosphere.

The entire unit can be located inside a structure by attaching concentric conduits to flanges and 91 and communicating these conduits with the atmosphere. The combustion air is then ducted from the atmosphere. The unit then embodies what is'l tnown as a sealed combustion system.

When the fan is running, the fluid pressure outside heat exchanger 24 will be greater than the inside stationary heat exchanger 24, thereby insuring that combustion products will not enter the conditioned air stream at 70. This condition can be assured by providing a control interlock between the fan motor 16 and the gas supply valve (not shown) which will always insure fan rotation before gas is supplied to noule 44:

Most preferably the design will be such that the pressure differential between the inside and outside of heat exchanger 24 will be maintained at a minimum under all conditions, but always slightly positive on the conditioned air side. A seal can also be employed ingap 70 to eliminate leakage.

In the embodiment shown in FIG. 1 a substantially circular cooling coil 72 is situated on flange 74 of casing 2. The cooling coil extends from flange 74 to the top portion 76 of housing 6. The cooling coil 72 is supplied with a cooling fluid through conduit 78. The cooling fluid is returned to its source (not shown) through conduit 80.

FIG. 3 shows a horizontal cross-sectional view of the heating-cooling air moving unit of FIG. 1 taken along section A-A. The numbers utilized in FIG. 3 correspond with those of FIGS. 1 and 2. Structural arms 4 attaching the casing 2 to outer housing 6 are shown. Only a portion of the stationary blades 26 are illustrated. Outlet flue 68 extends from stationary heat exchanger 24 through plenum 50 to its discharge end 82.

FIG. 4 is a cross-sectional view taken along line B-B of FIG. 2. This FIG. shows the upper portion of the rotating fan member containing the impellers 56. Impellers 56 are attached both to the rotating housing 18 and to the hub member 84 onto which shaft 14 is attached.

In operation the combined cooling-heating and air moving unit of FIGS. 1 and 2 draws in air from a suitable duct system into the annular space 86 between casing 2 and outer housing 6. The air thus flowing in the direction of arrows 88 moves upwardly and through coils 72 where it is drawn by fan blades 60 across rotating member 18 and pushed past stationary heat exchanger 24 and blades 26. The conditioned air is then returned in the direction of arrows 62 through a suitable duct system to the area being conditioned. During the summer season cooling fluid is, of course, supplied to coil 72 and no combustion occurs in combustion chamber 28. During the heating season no cooled fluid is supplied to coil 72 but a combustible fluid is burned in combustible chamber 28 and heat transferred through the rotating heat exchanger 18 and stationary heat exchanger 24 to the air or fluid being moved over the outer surfaces thereof.

It is of course understood that conventional control systems are readily adaptable for use with the present unit. Thermostatic controls for the cooling fluid and for the combustible fluid fired heat exchanger are readily available, as are interlock controls for fan motor 16 and combustible fluid supply 46.

The integral fan-heat exchanger of the present invention combines two functions into a single apparatus thus reducing required space for such an air conditioning unit. Furthermore, the integral fan-heat exchanger shown and described herein need be no larger than a conventional axial flow.

We claim:

1. An integral fan-heat exchanger comprising:

a. a first substantially cylindrical casing having an inlet and an outlet;

b. a combustion chamber mounted within said first casing, means for introducing a combustion fluid into said chamber, means for introducing a combustible fluid into said chamber and burning it herein, said chamber having an outlet for products of combustion;

c. a primary heat exchanger mounted for rotation within said first casing, said primary heat exchanger surrounding a portion of said chamber including said chamber outlet and thereby being in internal fluid communication with said chamber, said primary heat exchanger having an annularly shapedoutlet located between one end of said primary heat exchanger and the outside of said chamber,

said heat exchanger outlet being downstream of said chamber outlet, said primary heat exchanger having fluid moving blades extending radially therefrom and spaced from said first casing, said blades in heat exchange relationship with said primary heat exchanger;

d. a secondary heat exchanger mounted concentrically between said chamber and said first casing, said secondary heat exchanger in fluid communication with said primary heat exchanger,

e. means for exhausting products of combustion from said secondary heat exchanger;

f. motor means for rotating said primary heat exchanger.

2. The integral fan-heat exhanger of claim 1 wherein said fluid handling blades are hollow and the hollow portion in fluid communication with the interior of said primary heat exchanger, said blades positioned to draw unheated fluid into said first casing inlet; contact said air with said heat exchangers and drive the thus heated fluid out of said first casing outlet,

3. The integral fan-heat exchanger of claim 1 wherein the outer portion of said second heat exchanger inlet is spaced radially outward from said primary heat exchanger and upstream of the outer portion of said primary heat exchanger inlet.

4. The integral fan-heat exchanger of claim 2 wherein said primary heat exchanger has internally mounted blade means for assisting the flow of combustion gases from said chamber, into said hollow blades and into said secondary heat exchanger.

5. The integral fan-heat exchanger of claim 4 further including blades mounted on said secondary heat exchanger extending radially outward toward and spaced from said casing, said blades in heat exchange relationship with said secondary heat exchanger.

6. The integral fan-heat exchanger of claim 1 mounted in a second casing, said second casing having an inlet for air to be conditioned and an outlet for conditioned air, the inlets of said first and second casings in fluid communication through an inlet passage, said outlets of said first and second casings in fluid communication through an outlet passage, means for introducing a combustion fluid and a combustible fluid into said combustion chamber from outside said first casing, means for exhausting products of combustion to the outside of said first casing. 

1. An integral fan-heat exchanger comprising: a. a first substantially cylindrical casing having an inlet and an outlet; b. a combustion chamber mounted within said first casing, means for introducing a combustion fluid into said chamber, means for introducing a combustible fluid into said chamber and burning it herein, said chamber having an outlet for products of combustion; c. a primary heat exchanger mounted for rotation within said first casing, said primary heat exchanger surrounding a portion of said chamber including said chamber outlet and thereby being in internal fluid communication with said chamber, said primary heat exchanger having an annularly shaped outlet located between one end of said primary heat exchanger and the outside of said chamber, said heat exchanger outlet being downstream of said chamber outlet, said primary heat exchanger having fluid moving blades extending radially therefrom and spaced from said first casing, said blades in heat exchange relationship with said primary heat exchanger; d. a secondary heat exchanger mounted concentrically between said chamber and said first casing, said secondary heat exchanger in fluid communication with said primary heat exchanger, e. means for exhausting products of combustion from said secondary heat exchanger; f. motor means for rotating said primary heat exchanger.
 2. The integral fan-heat exhanger of claim 1 wherein said fluid handling blades are hollow and the hollow portion in fluid communication with the interior of said primary heat exchanger, said blades positioned to draw unheated fluid into said first casing inlet; contact said air with said heat exchangers and drive the thus heated fluid out of said first casing outlet.
 3. The integral fan-heat exchanger of claim 1 wherein the outer portion of said second heat exchanger inlet is spaced radially outward from said primary heat exchanger and upstream of the outer portion of said primary heat exchanger inlet.
 4. The integral fan-heat exchanger of claim 2 wherein said primary heat exchanger has internally mounted blade means for assisting the flow of combustion gases from said chamber, into said hollow blades and into said secondary heat exchanger.
 5. The integral fan-heat exchanger of claim 4 further including blades mounted on said secondary heat exchanger extending radially outward toward and spaced from said casing, said blades in heat exchange relationship with said secondary heat exchanger.
 6. The integral fan-heat exchanger of claim 1 mounted in a second casing, said second casing having an inlet for air to be conditioned and an outlet for conditioned air, the inlets of said first and second casings in fluid communication through an inlet passage, said outlets of said first and second casings in fluid communication through an outlet passage, means for introducing a combustion fluid and a combustible fluid into said combustion chamber from outside said first casing, means for exhausting products of combustion to the outside of said first casing. 